Python TCP socket.error with long messages

Question

I'm trying to send a basic message across my LAN network via TCP in Python.

TCPClient.py:

import socket, sys, time

TCP_IP = "10.0.0.10"
TCP_PORT = 5005
BUFFER_SIZE = 1024
running = True

while running == True:
    try:
        MESSAGE = raw_input("Message: ")
        s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
        print("Connecting...")
        s.connect((TCP_IP,TCP_PORT))
        print("Connected!")
        s.send(MESSAGE)
        data = s.recv(BUFFER_SIZE)
        s.close()

        print("Sent data: %s" % MESSAGE)
        print("Recieved data: %s" % data)
        running = False
        time.sleep(20)
    except socket.error as e:
        print(e)
        time.sleep(1)
    except:
        print(sys.exc_info()[0])
        time.sleep(1)

And TCPServer.py:

import socket, time, sys

TCP_IP = "10.0.0.10"
TCP_PORT = 5005
BUFFER_SIZE = 20

while True:
    try:
        s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
        s.bind((TCP_IP,TCP_PORT))
        print("Listening for connection...")
        s.listen(1)

        conn,addr = s.accept()
        while 1:
            data = conn.recv(BUFFER_SIZE)
            if not data: break
            print("Recieved data: %s" % data)
            conn.send(data.upper())
            print("Sent data: %s" % data.upper())
        conn.close()
    except TypeError as e:
        print(e)
    except ValueError as e:
        print(e)
    except socket.error as e:
        print(e)
    except:
        print(sys.exc_info()[0])
        time.sleep(1)

It mostly works for small messages (like "hello world") but when I send a message more than ~10 characters it splits it into 2 sections and sometimes doesn't even send half of it. E.g:

Answer 1

Here's what happened:

1. your client sent long line
2. your server got 20 characters of that long line (that's size of your buffer on server side)
3. your server sent back data (20 characters of line) to client
4. your client got data and disconnected from server, causing server to raise exception.